Record every alarm
Location, type, model and installation/replacement date are useful.
Follow local rules
Required locations and alarm types differ by jurisdiction.
Use certified products
Look for the safety certification required where you live.
Treat an alarm as an alarm
If a CO or smoke alarm sounds, follow emergency guidance rather than trying to diagnose the source yourself.
Safety boundary. This site is for planning, observation and records. Do not improvise electrical, fuel-burning, structural, roof-height or other hazardous work. Follow manufacturer instructions, applicable codes and qualified professional guidance.